1. Field of the Invention
The present invention relates to a method and an apparatus for detecting and alerting of patients' bed-departure using a sock embedded with a pressure sensor and a microcontroller unit to trigger an alert on a caretaker's monitoring unit.
2. Description of the Prior Art
The population of seniors who suffer from Alzheimer's, dementia, and other medical conditions has increased in recent years. Their frequent accidents and injuries as a result of wandering out of bed cause significant stress to their caretakers at home as well as those in hospitals and nursing facilities. There is an increasing need for detecting and alerting of such bed departures to protect the safety of these patients and reduce the stress of their caretakers.
Prior art has used load sensors installed on a patient's bed to detect his or her bed departure. The art disclosed in patent document 1 uses weight information to determine whether a user is still on the bed or has left the bed. The arts disclosed in patent documents 2 to 4 calculate the center of gravity from the weight information of four points on the bed, and use the center-of-gravity position information to monitor the movement of a user in bed.
All of the prior art inventions for bed-departure detection require specialized beds installed with load sensors. The associated costs and cumbersome set-up prevent their wide applications in homes as well as in nursing facilities and hospitals.
On the other hand, there are patent and non-patent prior art on shoes and socks embedded with sensors. The art disclosed in patent documents 5 through 9 and patent document 12 use pressure sensors on athletic shoes to measure strides length, running speed and other stride characteristics for sport training purposes. The art disclosed in patent document 10 uses strain sensors on a shoe to monitor patient force during rehabilitation. The art disclosed in patent document 11 uses force sensors on a shoe insole for remote gait analysis. The non-patent document 1 is a sensor sock for measuring plantar pressure used in the diagnosis of peripheral neuropathy. None of the prior arts on shoes or socks with sensors addresses the needs for detecting bed-departure of wondering patients.
Prior Arts on Bed-Departure Detection:
    Patent Document 1: Japanese Laid-Open Patent Application No. 2-280733    Patent Document 2: Japanese Patent No. 3093745    Patent Document 3: Japanese Patent No. 3322632    Patent Document 4: U.S. Pat. No. 5,276,432Prior Arts on Shoes, Insoles, and Socks with Pressure/Force Sensors    Patent Document 5: U.S. Pat. No. 4,736,312    Patent Document 6: U.S. Pat. No. 5,221,088    Patent Document 7: U.S. Pat. No. 5,343,445    Patent Document 8: U.S. Pat. No. 5,452,269    Patent Document 9: U.S. Pat. No. 5,471,405    Patent Document 10: U.S. Pat. No. 6,122,846    Patent Document 11: U.S. Pat. No. 6,360,597    Patent Document 12: U.S. Pat. No. 8,280,681    Non-Patent Document 1: Sensor Sock, www.csiro.au.